/**
 *    Copyright (C) 2025-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the Server Side Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */
#pragma once

#include "mongo/db/service_context.h"
#include "mongo/executor/task_executor.h"
#include "mongo/util/modules.h"

#include <list>
#include <memory>

namespace mongo {
namespace MONGO_MOD_PUBLIC executor {

struct ExecutorPair {
    std::weak_ptr<TaskExecutor> pinned;
    std::weak_ptr<TaskExecutor> underlying;
};

/**
 * Registers a (pinned, underlying) ExecutorPair in the Registry on construction and unregisters the
 * same pair on destruction.
 */
class PinnedExecutorRegistryToken {
public:
    PinnedExecutorRegistryToken(ServiceContext* svc,
                                std::shared_ptr<TaskExecutor> pinned,
                                std::shared_ptr<TaskExecutor> underlying);
    ~PinnedExecutorRegistryToken();

private:
    ServiceContext* _svc;
    // Iterator to this token's registry entry.
    std::list<ExecutorPair>::iterator _it;
};

// Shutdown and join all pinned executors that were built on top of 'underlying'.
void shutdownPinnedExecutors(ServiceContext* svc, const std::shared_ptr<TaskExecutor>& underlying);

}  // namespace MONGO_MOD_PUBLIC executor
}  // namespace mongo
